Re: [Discuss-gnuradio] gr-ieee 802.11 Wifi Transceiver Issue

[Abhinav Jadon]

Hi Bastian,

There are no overruns and the connections to the antenna ports are correct.

The frame detection is working

I tried all the stuff you told me to try ie I tried LMS ansd LO offset, they worked as in I saw some packets being decoded by the wireshark connector. But the packet content was incorrect . Each packet decoded looked like this


new mac frame  (length 10)
=========================================
frame too short to parse (<20)
WIRESHARK: received new message
message length 10
WIRESHARK: d_msg_offset: 0   to_copy: 43   d_msg_len 43
WIRESHARK: output size: 32768   produced items: 43

While the packet that is being transmitted has the following characteristics

WIRESHARK: received new message
message length 624
WIRESHARK: d_msg_offset: 0   to_copy: 657   d_msg_len 657
WIRESHARK: output size: 32768   produced items: 657

Is the signal field being wrongly interpreted ?

Regards

Abhinav PS  Jadon

2012122
Electronics and Communication Engineering Undergraduate
IIIT - Delhi
IASc Summer Research Fellow 2015
E: address@hidden

M: +919650936845

On Thu, Feb 11, 2016 at 6:13 AM, Bastian Bloessl <address@hidden> wrote:

Hi

> On 10 Feb 2016, at 15:13, Abhinav Jadon <address@hidden> wrote:
> Next I replaced the loopback with a uhd source and sink and connected the RF frontends using a SMA cable. It fails to give me any packet (the wireshark connector). I tried playing with the value of rx_gain and tx_gain. I also tried playing with the value of the the correlation threshold.
> I then chose to debug using the data flow. The data in the flowgraph flows until the Decode MAC block where it gets dropped with checksum wrong message.
>

Your debugging sounds already pretty good. Some more stuff you could try

- assert that there are no overruns (‘O’s or ‘D’ on the console)
- check that frame detection is working (there are no frames detected when the transmitter is turned off)
- test with antennas
- assert that you connected the correct antenna ports (RX and TX use a different ports by default)
- set a different LO offset
- use the LMS equaliser
- try a different sample rate / bandwidth
- check if the signal field is decoded correctly (log or debug option)

Best,
Bastian